Coil expander



I Aug. 23, 1966 R. RAHN 3,268,181

COIL E XXXXX ER Original Filed June 28, 1962 United States Patent3,268,181 COIL EXPANDER Richard Rahn, Dusseldorf, Germany, assignor toSchloemann Aktiengesellschaft, Dusseldorf, Germany, a company of GermanyOriginal application June 28, 1962, Ser. No. 205,975, now Patent No.3,216,671, dated Nov. 9, 1965. Divided and this application May 18,1965, Ser. No. 456,777 Claims priority, application Germany, July 25,1961, Sch 30,037 Claims. (Cl. 24278.1)

This application is a division of my application Ser. No. 205,975, filedJune 28, 1962, now Patent No. 3,216,- 671, which issued November 9,1965.

The products coming from a cold-rolling mill are as a rule annealed,after the cold-rolling, in an atmosphere of protective gas. Sheet-ironstrips, which require to be maintained at the annealing temperature forrather a long time, are usually annealed in a coiled condition, that isto say, as a complete bunch or coil. Now it is known that duringannealing in an atmosphere of protective gas, as loose a Stratificationas possible of the material to be annealed leads to a better scavengingof the stack of material that is being annealed with the protective gas,and therefore to a better removal of impurities, a quicker heating up,and a more uniform texture-formation. Now since a bunch of strip comingfrom the cold-rolling mill is usually very stiff and tightly coiled, oneis nowadays frequently constrained, for the purpose of obtaining a looselayering, to open out the tightly coiled bunch of strip by re-windingit, that is, by re-shaping it in such a way as to provide, between theindividual turns, spaces through which the protective gas can be passedduring the annealing process.

A re-winding appliance is known which serves to convert strip-iron ringsof a given diameter to a larger diameter. With this appliance the stripring to be converted is placed with one of its end faces upon astationary table, the outer end of the strip being secured to the innerperipheral surface of a clamping ring embracing the ring of strip, andthe clamping ring being set in rotation in a direction opposite to thewinding direction of the strip ring, whereby the individual turns of thestrip ring, advancing in an inward direction, travel outwards, and bearon the rotating clamping ring.

In another appliance on the same principle, for the better centering ofthe strip ring, a mandrel penetrating cen trally through the bearingsurface is provided, or else a row of concentrically arranged rods aresecured upon the bearing surface, and it is the mandrel, with the ringof strip mounted thereon, that is set in rotation, instead of the outercasing. Here the bearing surface is divided into an inner disc and anouter ring, and the inner disc revolves along with the mandrel. It Wouldof course also be possible to let the mandrel, with the tightly coiledbunch mounted thereon, turn in the opposite direction simultaneouslywith the outer clamping ring.

When re-winding with such an appliance, the tensile stress usuallyprevailing in a tightly coiled bunch of strip can be considerablyreduced, that is to say, quite loose and soft bunches can be produced.Now it has been found that in the re-coiling, particularly ofthin-strips, the speed of re-winding has a great influence upon thestrength of the newly formed coil, in such a way that at a highrewinding speed (a great speed of revolution of the mandrel or of theouter casing, or of both), looser coils are obtained than with a lowerspeed of re-winding. By tests and measurements it has been ascertainedthat this is effected by damming or impounding air, which, withincreasing speed of winding, acts in the form of compressive and suctionforces upon the turn that happens to be travelling outwards.

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The invention on which the problem is based, of producing opened coilswith the spaces between the turns as uniform and regular as possible,harks back to the last appliances described, since these are of verysimple construction, are economical in the use of space, and operatevery reliably, particularly as regards injuries to the surface of thestrip, the unwinding and re-winding of the strip that is otherwise usualin the production of an opened coil being obviated. Now in order toobtain the desired spacing between the individual turns, means are to beprovided by which the action of the impounding of air, yielded whenre-winding at a high winding speed, is reinforced in such a way that inthe formation of the coil of larger diameter, the turns are preventedfrom coming into contact with one another.

According to the invention this object is achieved by providing in theseknown appliances, a cover plate covering the upper end of the coil in anairtight manner. By this means the air that is displaced from the turnthat is travelling outwards cannot escape outwards, but bears like acushion or pad between the preceding turn that is already formed and thefresh turn now being formed. At the same time, however, no air fromoutside can enter the interior of the coil, whereby the suction arisingbehind the travelling turn is reinforced. Adequate driving power must ofcourse be provided for a sufliciently high re-winding speed.

According to a further feature of the invention, a drive maintaining aconstant speed of revolution of the mandrel and/or the outer casing willbe provided, so as to keep the distances between the turns uniform.

One embodiment of apparatus according to the invention isdiagrammatically illustrated by way of example in the accompanyingdrawings, in which:

FIGURE 1 shows in section a side view of the apparatus; and

FIGURE 2 shows a plan view in section on the line IIII in FIGURE 1.

Upon a circular base-plate 1 are arranged a rather large table-ring 2,and a smaller ring 3. The table-ring 2 is rotatably supported, but theinner ring 3 is stationary, being secured non-rotatably upon thebase-plate 1. The table-ring 2 is stepped up towards the periphery,comprising a raised step 2a all round, and a collar 2b projecting abovethe step 2a. The table-ring 2 carries a number of individual rings 4, 5,6 and 7 of different sizes, which are arranged one in another likehearth-rings, and which are free to rotate slidingly upon the table-ring2 independently of one another. The upper surfaces of the rings 3, 4, 5,6 and 7 are flush with one another, so as to form a plane bearingsurface for the accommodation of the bunch or coil of strip 8. In thecentre of the apparatus a vertical core or mandrel 9 is provided, whichserves as a pivot, and which is equipped with a clamping device 10 forthe inner end of the coiled strip. If desired, the mandrel 9 may bejournaled in a bearing bush 19, and driven by a motor 20. The table-ring2 is provided with external teeth, which mesh with a toothed pinion 11,driven by a motor 18. The table-ring also carries a cylindrical outercasing 12, which is held by the collar 2b, and is provided with a numberof slits 13 distributed around the periphery, in which a cover plate 14,covering the whole of the upper end of the coiled bunch 8, 8a, can besecured at an adjustable height. Means for holding fast the cover plate14 on the mandrel 9 may of course alternatively be provided.

The apparatus according to the invention operates in the followingmanner: After the bunch of strip 8 to be opened has been placed upon theapparatus, and the inner end of the strip has been clamped by means ofthe clamping device 10, the cylindrical outer casing 12 is put on andthe outer end of the strip is so far loosened that it describes a largeenough circle, and can be secured to the inner wall surface of the outercasing 12 by means of a clamping device not shown. The cover plate 14 isthen put on, and upon this cover plate a ring 16 is laid. Clampingscrews 17, slidable in vertical guiding slots 13 in the outer casing 12,engage in the ring 16, and enable this ring and the cover plate to besecured in such a way that the cover plate just touches the upper edgeof the bunch 8. The rotational drive 11 is now switched on, this beingso arranged that the table ring 2, and with it the outer casing 12 also,revolve at a high speed in the direction of the arrow 15. The leadingend of the strip, secured to the outer casing 12, is carried round withthe casing, with the result that the strip section, extending in aspiral path of large pitch towards the stationary bunch, is movedoutwards in an unwinding direction, towards the outer end of the strip,or, in other words, towards the outer casing 12, a corresponding freshsection of a turn being from time to time lifted off the tightly Woundbunch. On the basis of the high speed of revolution, the outwardlytravelling turns move very quickly, so that the air impelled by the turnthat is running oif forms a sort of thrust wave, whilst'at the sametime, behind this turn, there is suction. Now since, owing to thecovering of the upper end of the coil, air cannot escape outwards, norcan atmospheric air enter the winding space, and the equalization of airin the Winding space is itself subject to a certain time lag, thepressure and suction forces occurring are strong enough to preclude theoutwardly moving turn section from contact with the turn previouslyformed. When once a turn section has come to a standstill, it does notundergo any further displacement.

It is in order as far as possible to obviate, in the winding operation,any grinding of the lower edge of the strip upon the bearing surface,that the bearing surface is divided into a number of individual rings 4,5, 6 and 7. Those individual rings that are loaded by the stationarybunch 8, for instance the rings 6 and 7, are here held fast by theweight loading them, so that as the table-ring 2 is driven the latterturns beneath the rings 6 and 7. In

the course of the winding operation, turn after turn is re-.

leased from the stationary coiled bunch and moved radially outwards, sothat one ring after another is relieved of load. The unloaded rings 4, 5and 6 are then from time to time carried round by the revolvingtable-ring. The turns 8a, that are already released, rotating along withthe outer casing 12, thus receive a bearing surface turning with them,and therefore relatively stationary.

Now in order to obtain, in the coiling operation, as high a speed ofre-coiling as possible, it is of course quite possible not only to havethe outer casing 12 revolving but to have the mandrel 9, with the tightcoil of strip 8, also revolving, but in the opposite direction. Withsuch an arrangement, however, care must be taken that the positivelydriven members, the outer casing 12 and the mandrel 9, turn at asconstant a speed as possible, in order that in the opened bunch, uniformand satisfactory spaces should be formed between the turns. By changingthe coiling speed, the spacing between the turns can be slightlyaltered.

This apparatus, which is also suitable for re-winding non-metallicstrips, can however only be employed for thin Y and quite flexiblestrips, up to a maximum thickness of half a millimetre. An expedient foralso enabling coils of thicker strip material to be opened, or forobtaining wider spacing between the individual turns, consists infilling the apparatus with a fluid heavier than air. The outwardlytravelling turns will hereby be opposed by a greater weight. Such aheavier medium might for instance be carbon dioxide; and by appropriateadditions of other gases a cleaning of the strip from residues of fat oroil can at the same time be effected. The apparatus must of course thenbe made gastight, to comply with protective regulations.

I claim:

1. Apparatus for re-shaping a tightly coiled bunch of strip materialinto an opened bunch with spaced turns, comprising: a base-plate, aplane bearing surface for the endwise mounting of the tightly coiledbunch of strip, the bearing surface cosnisting of a number of concentricrings resting on the base-plate and slidingly rotatable independently ofthe base-plate and independently of one another, a central mandrelextending upwards through the said bearing surfam, a cylindrical outercasing surrounding the bearing surface, a clamping device for securingthe outer end of the strip to the outer casing, and a cover plateadapted to rest in a substantially airtight manner on the top end of acoil of strip located within the cylindrical outer casing, so that byrotating the outer casing relatively to the mandrel, turn after turn ofthe strip is lifted away from the tightly coiled bunch and movedoutwards towards the outer casing.

2. Apparatus for re-shaping a tightly coiled bunch of strip materialinto an opened bunch with spaced turns as claimed in claim 1, furthercomprising means for fixing the cover plate at an adjustable height.

3. Apparatus for re-shaping a tightly coiled bunch of strip materialinto an opened bunch with spaced turns as claimed in claim 1, furthercomprising a drive adapted to keep the re-winding speed constant.

4. Apparatus for re-shaping a tightly coiledbunch of strip material intoan opened bunch with spaced turns as claimed in claim 1, the windingspace enclosed in a gastight manner by the bearing surface, thecylindrical outer casing and the cover plate being filled with a mediumthat is heavier than air.

5. Apparatus for re-shaping a tightly coiled bunch of strip materialinto an opened bunch with spaced turns as claimed in claim 4, the saidmedium also including gases capable of removing contaminations such asgrease from the strip.

References Cited by the Examiner UNITED STATES PATENTS 2,366,352 1/1945Paxson 242--78.1 3,008,663 11/1961 Blackman et al. 24278.l X 3,064,91811/1962 Keen et al. 24278.1

MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATH, Examiner.

N, L. MINTZ, Assistant Examiner.

1. APPARATUS FOR RE-SHAPING A TIGHTLY COILED BUNCH OF STRIP MATERIALINTO AN OPENED BUNCH WITH SPACED TURNS, COMPRISING: A BASE-PLATE, APLANE BEARING SURFACE FOR THE ENDWISE MOUNTING OF THE TIGHTLY COILEDBUNCH OF STRIP, THE BEARING SURFACE CONSISTING OF A NUMBER OF CONCENTRICRINGS RESTING ON THE BASE-PLATE AND SLIDINGLY ROTATABLE INDEPENDENTLY OFTHE BASE-PLATE AND INDEPENDENTLY OF ONE ANOTHER, A CENTRAL MANDRELEXTENDING UPWARDS THROUGH THE SAID BEARING SURFACE, A CYLINDRICAL OUTERCASING SURROUNDING THE BEARING SURFACE, A CLAMPING DEVICE FOR SECURINGTHE OUTER END OF THE STRIP TO THE OUTER CASING, AND A COVER PLATEADAPTED TO REST IN A SUBSTANTIALLY AIRTIGHT MANNER ON THE TOP END OF ACOIL OF STRIP LOCATED WITHIN THE CYLINDRICAL OUTER CASING, SO THAT BYROTATING THE OUTER CASING RELATIVELY TO THE MANDREL, TURN AFTER TURN OFTHE STRIP IS LIFTED AWAY FROM THE TIGHTLY COILED BUNCH AND MOVEDOUTWARDS TOWARDS THE OUTER CASING.